Cavity walls incorporating metal cavity wall ties have been used since the 19th century. Since the 1950’s the cavity wall has become the standard form of construction for housing and buildings of a similar scale. The structural integrity of many buildings is partially dependent on the use of cavity wall ties in the construction.

Over time, however, the process of corrosion of mild steel cavity wall ties causes expansion of the cavity wall ties because the metallic oxide occupies a greater volume than the pure metal. This expansion has the effect of forcing apart the bricks above and below the bed joints in which the ties are laid, producing a pattern of horizontal cracks coinciding with the tie positions approximately every six courses. The corrosion of the cavity wall ties or the lack of sufficient cavity wall ties used in the original construction means that many properties require either further replacement wall ties to be inserted or a complete cavity wall tie replacement to be carried out.

Cavity wall ties replacement is a straight forward procedure, identify the positions of existing cavity wall ties; install neoprene wall ties or replacement wall ties from our range in positions staggered from the original cavity wall ties. Wall tie replacement should be carried out in a uniform spacing pattern: a diamond formation with remedial wall ties at 900mm centres in courses set 450mm apart. At door and window openings the spacing is reduced to 300mm vertically.

The original cavity wall ties need to be isolated to prevent further damage to the cavity wall. Isolation of the cavity wall ties can be achieved by fitting Clan Sleeves around the external end of the cavity wall tie or complete removal of the cavity wall tie which will mean removal of bricks to release the tie.

Permagard’s range of replacement wall ties:

Easi-Fix Neoprene Wall Ties: A replacement wall tie made from 304 stainless steel with Neoprene expanders, the tie is mechanically tightened with a drill which expands the inner and out leaf of the replacement wall tie gripping the tie into place.

Easi-Fix Helical Drive Ties: A replacement wall tie manufactured from 304 stainless steel. A 5-6mm pilot hole is drilled into the substrate into which the replacement wall tie is placed, the tie is then driven through the outer leaf into the inner leaf with a hammer drill. The tie has fins that cut and grip into the substrate holding the inner and outer leaf in place.

Easi-Fix Threaded Bar Ties: A replacement wall tie manufactured from 304 stainless steel. The tie is inserted into a pre drilled 10mm hole the wall and fixed in place with polyester resin or an anchor grout. The bar grips the resin which in turn grips the substrate holding the cavity in place.

Our technical staff are able to advise you on all aspects of cavity wall ties replacement for any job large or small. Whether you need a specialist installer in your area or help with a specification our technical advisors are here to help. Simply call us on 01179 381 596.